1. Field of the Invention
The present invention relates to a color filter used for a liquid crystal display apparatus, and a liquid crystal display apparatus including the color filter.
2. Description of the Related Art
The Applicant of the present invention has previously filed an application for the invention titled "Liquid Crystal Apparatus" (Japanese Patent Application No. 8-341591).
The above-mentioned invention relates to a liquid crystal display apparatus with a high contrast and outstanding viewing angle characteristics in which a liquid crystal layer is interposed between a pair of substrates, a color filter is provided on one substrate, and a homeotropic alignment film is formed on the surface of a black mask of the color filter.
FIG. 13 is a schematic cross-sectional view of the liquid crystal display apparatus. As shown in this figure, a liquid crystal layer 102 is interposed between a pair of substrates 101. A color filter 103 is provided on the lower substrate 101. A display surface is partitioned by a black mask 104 of the color filter 103, whereby each display region 105 is formed. An alignment film 106 is formed on the color filter 103, and a homeotropic alignment film 106a is formed on each surface of vertical walls of the black mask 104 of the color filter 103.
In a case where the homeotropic alignment film 106a is formed on each surface of the vertical walls of the black mask 104, since a liquid crystal material containing liquid crystal molecules 102a having negative .DELTA..epsilon. (anisotropy of dielectric constant) is used, liquid crystal molecules 102a in the liquid crystal layer 102 are aligned in a vertical direction to the substrates 101 while a voltage is not applied across the substrates 101, and the liquid crystal molecules 102a of the liquid crystal layer 102 are tilted from the vertical direction while a voltage is applied across the substrates 101.
In this case, since each homeotropic alignment film 106a is present on either side of each display region 105 as shown in FIG. 14, each liquid crystal molecule 102a is tilted to be aligned so as to be axially symmetric. Thus, a liquid crystal display apparatus with a high contrast and outstanding viewing angle characteristics is obtained.
Even in a case where each liquid crystal molecule 102a is aligned so as to be axially symmetric in each display region 105 by forming the homeotropic alignment film 106a on the black mask 104, if beads with a small diameter are dispersed between the substrates 101 so as to keep a gap therebetween, the alignment of the liquid crystal molecules 102a is disturbed by the beads. As a result, the display surface becomes rough due to the shift of an axis position.
In order to solve the above-mentioned problem, each spacer 107 is arranged only on the black mask 104 as shown in FIG. 15, thereby preventing the spacers 107 from affecting the liquid crystal molecules 102a in each display region 105.
A method for producing the above-mentioned structure will be described below.
As shown in FIGS. 16A and 16B, the color filter 103 is formed on one of the substrates 101. Then, as shown in FIGS. 17A and 17B, each spacer 107 is arranged on the black mask 104 of the color filter 103. Each spacer 107 is fixed by a lattice-shaped wall 108 as shown in FIGS. 18A and 18B. The other substrate 101 is placed as shown in FIG. 15.
FIGS. 16A, 17A, and 18A are cross-sectional views, and FIGS. 16B, 17B, and 18B are plan views.
According to the above-mentioned method, it is difficult to place each spacer 107 only on the black mask 104 (not on each display region 105) as shown in FIG. 15. This complicates the production process, resulting in an increase in cost.